This proposal focuses on the marriage of solid-state electronics and neuronal function to create a new high-throughput electrophysiological assay to determine a compound's or gene product's acute and chronic effect on a cell's function. We have integrated electronics, surface chemistry, biotechnology, genomics and fundamental neuroscience in a concept involving an assay where the reporter element is an array of electrically active cells. This innovative technology has potential to screen compounds from combinatorial chemistry, gene function analysis, and for basic neuroscience applications. Because the method is non-invasive, temporal analysis on a statistically relevant number of cells would now be possible. This would be a benefit over intracellular electrophysiology which perforates the membrane and kills the cell within 4-8 hours. Specific Aim 1 seeks to employ surface chemistry to establish a higher resistance seal between a NE108-15 cell and a metal microelectrode that recreates the interface that is present in patch-clamp electrophysiology utilizing glass micropipettes, so as to allow high fidelity extracellular electrophysiology on a microelectrode array. Specific Aim 2 relies on our previous research in which we used cultured neuronal cells as sensor elements for generic toxin detection. During the course of this study, we observed that most of the toxins tested stopped the action potential. However, how the action potential was interrupted showed differences that we postulate are due to individual toxins acting on different biochemical pathways, which in turn affect ion channels differentially, thereby changing the peak shape of the action potential in a unique manner for each toxin. We propose that algorithms developed jointly between UICU, UCF and CFDRC to analyze the action potential peak shape differences can be used to indicate the pathway(s) or cellular "functional categories" affected by the introduction of a compound to the system or from the activation of a gene. We believe this observation can ultimately be exploited to determine the functional category of biochemical action of unknown compounds or genes. Specific Aim 3 will combine these two advances to demonstrate the feasibility of using living cells as diagnostics for high throughput real-time assays of cell function. This would create a new diagnostic tool to enable the segregation of the effect of a compound or gene product on a cell's function into categories simply by monitoring changes in the action potential on a statistically relevant number of cells that is readily integrated with information obtained by other methodologies currently under development by CFDRC. This approach has the added capability to evaluate function temporally as well as under a variety of conditions, or at different times in a cell's lifecycle. The Nanoscience Technology Center at the University of Central Florida is lead for this proposal with collaborators from the University of Illinois and CFD Research Corporation, Huntsville, AL. [unreadable] [unreadable] [unreadable]